Rotted Ones, Lay Siege

If one of these Zombies can’t attack its designated player during any given turn (because that player has left the game, due to a spell or ability such as Chronomantic Escape, or because a player on the opposing team has gained control of it, for example), it may attack another player, attack a planeswalker an opponent controls, or not attack at all. If there’s a cost with having that creature attack its designated player, you aren’t forced to pay that cost, so it may attack another player, attack a planeswalker an opponent controls, or not attack at all.